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<ul><li><p>Environmental Risk Assessment for Shale Gas Development </p><p>Daniel J. Soeder, NETL, Morgantown, WV </p><p>Presentation for Chesapeake Bay Program STAC </p><p>State College, PA, April 11, 2012 </p></li><li><p>2 </p><p>Concepts of Risk </p><p>Risk = probability x consequences </p></li><li><p>3 </p><p>Risk in Engineered Geologic Systems </p><p> Threat: external events that cause risk </p><p> Threats can exploit vulnerabilities </p><p> Threats are assessed in terms of probability (Precautionary Principle) </p><p> Vulnerability: internal weakness that invites risk </p><p> Vulnerability only exists in the face of a threat </p><p> Vulnerability is assessed in terms of likely threats (Calculated Risk) </p><p> Both threats and vulnerabilities must be assessed to </p><p>properly understand risk. </p><p>Risk can vary over time &gt;&gt; </p><p>(CO2 injection example) </p></li><li><p>4 </p><p>NETL Office of Research and Development </p><p> New program charge in 2011 for </p><p>EPAct projects: Assess risk from oil </p><p>and gas production </p><p> Program Technical Areas: </p><p> Ultra-Deep Offshore/Frontier </p><p>Regions </p><p> Unconventional Resources, </p><p>primarily shale gas </p><p> Focus Areas for Risk Assessment: </p><p> Potential impacts from hydraulic </p><p>fracturing </p><p> Potential impacts from poor </p><p>wellbore integrity </p><p> Potential impacts to water quality </p><p> Potential impacts to air quality </p></li><li><p>5 </p><p>Potential Shale Gas Risks </p><p> Engineering Risk Assessment: </p><p> What is the probability of a contaminant release? </p><p> What is the probability of an induced seismic event? </p><p> What risks are short term versus long term? </p><p> What are the receptors? </p><p> Air, water, landscapes, ecosystems/habitat </p><p> The major unknown risk is cumulative effects </p><p> How will multiple wells make an impact? </p><p> What is threshold for impacts? (i.e. impervious surfaces) </p><p> Risk reduction through regulations and enforcement </p><p> Not all known environmental impacts are regulated </p><p> Not all regulations are fully enforced </p></li><li><p>6 </p><p>Risk Assessment in Engineered Systems </p><p> DOE National Risk Assessment Partnership (NRAP) Cooperative effort among NETL, LBNL, LLNL, LANL, and PNNL </p><p> Scenario-based, site modeling for carbon storage in engineered </p><p>geologic systems </p><p> Sometimes called site performance assessment </p><p> Uses FEP-based scenarios and probabilities Feature: property of a geologic system that may affect risk </p><p> Event: an action that introduces higher risk conditions into a system </p><p> Process: a method or procedure that increases risk </p><p> Predict performance of components using high fidelity </p><p>models </p><p> Run scenarios to validate models/reduce uncertainty </p><p> Provide quantitative basis for geologic storage security </p></li><li><p>7 </p><p>Integrated Risk Assessment Models </p><p> Integrated Assessment Models (IAM) Probabalistic assessment of system risk (multi-site) </p><p> Interaction of sites can increase or decrease risk </p><p> Divide system into components, develop detailed, </p><p>validated models, reduce uncertainty </p><p> Develop reduced order models (ROM) to reproduce </p><p>detailed model predictions of components </p><p> Integrate ROMs through IAM to predict total system </p><p>performance, interactions and risk </p><p> Calibrate using field data and databases </p><p> Quantify potential long-term liability </p><p>Risk Profile Risk Management Validation </p><p> (Quantify) (Strategy) (Field Data) </p></li><li><p>8 </p><p>Adapting NRAP to Shale Gas </p><p> Components: old wells with </p><p>potential casing and cement </p><p>integrity issues, watered-out </p><p>reservoirs </p><p> Design Basis: greatest risk </p><p>is immediately after injection; </p><p>when pressure is highest. </p><p> Model: seal integrity, well </p><p>bore leakage, migration </p><p>through intermediate strata, </p><p>changes in pressure and </p><p>saturation </p><p> Validation: monitoring, </p><p>verification and accounting </p><p> Components: new wells, </p><p>with new fractures, tight, dry, </p><p>overpressured reservoir </p><p> Design Basis: greatest risk </p><p>is after frac during early </p><p>stages of production under </p><p>initial high pressure. </p><p> Model: fracture heights, </p><p>fresh groundwater depth, </p><p>bypass flowpaths, wellbore </p><p>leakage, pressure/stress </p><p>changes </p><p> Validation: field monitoring </p><p>and analyses (need defining) </p></li><li><p>9 </p><p>Risk Assessment via Incident Reports One method to help determine the components of an IAM is to </p><p>review past incident data at oil and gas production sites. </p><p> Reporting only the number of incidents is meaningless: Discharge of industrial waste can range from a spilled quart of motor oil to a leak from a ten thousand </p><p>gallon frac fluid tank. </p><p> Classification of incidents: </p><p> Administrative: missing signage, poor record-keeping, incorrect permit application or </p><p>other missing or wrong "paperwork." </p><p> Minor: small spills or leaks that require clean up, but are contained on site, do not </p><p>enter the groundwater, and can be remediated by the local rig crew. </p><p> Significant: larger spills or leaks that could potentially leave the site but did not, and </p><p>required outside assistance (i.e. HAZMAT team) to help clean up. </p><p> Serious: explosion, fire, stream contamination or fish kill, human injury or fatality, </p><p>significant property damage, contamination of a drinking water supply. </p><p> Catastrophic: destruction of site and serious damage to surrounding area. </p><p> Frequency, type and seriousness of incidents over time help define </p><p>risk trends. </p><p> State regulatory agencies are the source of most incident reports. </p></li><li><p>10 </p><p>Water Contamination Incidents Kell, Scott, 2011, State Oil and Gas Agency Groundwater </p><p>Investigations and their Role in Advancing Regulatory Reforms: A Two-</p><p>State Review: Ohio and Texas, Groundwater Protection Council, 165 </p><p>p., August 2011, Oklahoma City, OK: </p><p> Incident: "any detected contamination of groundwater or disrupted water </p><p>supply due to development of oil and gas or management of wastes." </p><p> Ohio reported 144 incidents in 33,304 wells between 1983 and 2007 </p><p>(rate = 0.432%); no significant shale gas production at the time. </p><p> Most Ohio incidents occurred during drilling/production operations </p><p> 85 of the 144 incidents (60%) occurred between 1983 and 1988 (boom). </p><p> Texas reported 211 incidents in 187,788 wells between 1993 and </p><p>2008 (rate = 0.112%); Barnett Shale play began in 1997. </p><p> Most Texas incidents occurred during waste disposal </p><p> Texas RR Commission "witnesses" drilling and completion operations on </p><p>about 1/3 of wellsites </p><p> Both states reported zero incidents over the time periods studied </p><p>associated with well stimulation (hydraulic fracturing) </p></li><li><p>11 </p><p>Water Resource Risks/Questions Supply </p><p> 3 to 4 million gallons per well </p><p> 2/3 to 3/4 consumptive use </p><p> Watershed management vs. stress </p><p> Watershed Impacts Stream degradation from roads-pads-operations </p><p> Water quality degradation from leaks/spills </p><p> Groundwater Infiltration from above </p><p> Frac fluid/formation water from below </p><p> Changes in GW flow directions or gradients </p><p> Fate of fluids that remain underground </p><p> Water quality Infiltration of chemicals/spills into shallow </p><p>groundwater </p><p> Long-term leaching of drill cuttings </p><p> Minerals-sediment-gas contaminating nearby water wells </p><p>http://pubs.usgs.gov/fs/2009/3032/ </p></li><li><p>12 </p><p>Hydraulic Fracture Heights and Aquifers </p><p>0 </p><p>1000 </p><p>2000 </p><p>3000 </p><p>4000 </p><p>5000 </p><p>6000 </p><p>7000 </p><p>8000 </p><p>9000 </p><p>1 51 101 151 201 251 301 351 </p><p>Dep</p><p>th (</p><p>ft) </p><p>Frac stages (sorted on Perf Midpoint) </p><p>Marcellus Mapped Frac Treatments </p><p>fracTOP </p><p>perfTOP </p><p>Perf Midpoint </p><p>perfBTM </p><p>fracBTM Microseismic data, plotted against deepest freshwater aquifer on a county by county basis. </p><p>Reference: Fisher, Kevin, 2010, Data confirm safety of well fracturing, The American Oil and Gas Reporter, July 2010, www.aogr.com </p><p>http://www.aogr.com/</p></li><li><p>13 </p><p>Surface Leaks and Spills </p><p> Higher risk to groundwater and surface </p><p>water than frac fluid underground (Groat, </p><p>UT Austin study, 2012) </p><p> Baseline data on existing contaminants are </p><p>required to assess drilling impacts. </p><p> Studies underway in 2012: </p><p> Retrospective investigation of impacted </p><p>streams; large and small watersheds </p><p> Comparison of stream reaches: affected </p><p>and unaffected; also compare two similar </p><p>small watersheds (WVU) </p><p> Comparison of impacts versus watershed </p><p>management practices (Pitt) </p><p> Assessment of impacts, damage, costs </p><p> Forensics of what caused the leak </p><p> Better leak detection and warning, including </p><p>field-deployable instruments to monitor </p><p>surrogates (pH, conductance, turbidity) </p><p> Prospective data from Marcellus Test Site </p><p> Photo by Doug Mazer, used with permission. </p></li><li><p>14 </p><p>Geochemistry of Shale Drill Cuttings Vertical: 5 metric tons of cuttings </p><p> Horizontal: 270 metric tons of cuttings </p><p> Anoxic black shales preserved organic </p><p>material with associated radionuclides. </p><p> Highest gas content is in the organic-rich, </p><p>radioactive black shale; cuttings at surface </p><p>are exposed to air and rainwater </p><p> Oxidized forms of these metals are much </p><p>more soluble and mobile </p><p> TimeofFlight Secondary Ion Mass Spectrometry (TOFSIMS) to determine speciation of U and Cr (SUNY@Buffalo) </p><p> Uranium is associated with organics in the </p><p>shale, especially hydrogen. </p><p> Also investigating </p><p>how organics in </p><p>the shale might </p><p>oxidize and weather </p><p>UH+ on left, Hydrocarbons on right </p><p>&lt; Native sulfur on weathered Marcellus </p></li><li><p>15 </p><p>NE PA: Methane in Groundwater </p><p>Duke University study on 68 wells shows </p><p>methane in groundwater in NE PA occurs </p><p>in much higher concentrations near gas </p><p>wells, and concludes it is related to wells. (Osborn, Stephen G., Avner Vengosh, Nathaniel R. Warner, and </p><p>Robert B. Jackson, 2011, Methane contamination of drinking </p><p>water accompanying gas-well drilling and hydraulic fracturing: </p><p>PNAS Early Edition Direct Submission article, available on-line </p><p>only; Proceedings of the National Academy of Sciences, 5 p) </p><p>Baseline data on 1700 water wells prior to </p><p>gas drilling shows methane is common in </p><p>NE PA groundwater, and related to </p><p>topography (highest in stream valleys). (Molofsky, L. J., J.A. Connor, S.K. Farhat, A.S. Wylie, Jr., and </p><p>Tom Wagner, 2011, Methane in Pennsylvania water wells </p><p>unrelated to Marcellus shale fracturing: Oil &amp; Gas Journal, Vol. </p><p>109, no. 49, December 5, 2011, p. 54-67) </p><p>The proper question might be: how does </p><p>drilling affect domestic water wells when </p><p>methane is present in the aquifer? </p><p>Norma Fiorentino's exploded well vault </p></li><li><p>16 </p><p>Trapped, high pressure drilling air in fractured aquifer causes </p><p>groundwater surge, entraining and mobilizing pre-existing methane. </p><p>Surge is stronger closer to well, entraining more gas. Surge also </p><p>entrains minerals and sediment. </p><p>NETL is collaborating with Temple University and Duke University to </p><p>field test this conceptual model, and numerically model GW flow near </p><p>drill sites in Susquehanna Co. </p></li><li><p>17 </p><p>Range Resources Site for Baseline Monitoring </p></li><li><p>18 </p><p>Marcellus Test Site Monitoring Team </p><p>1. U.S. Dept. of Energy-NETL: Air emissions, soil gas surveys, </p><p>electromagnetic surveys for abandoned wells, avian surveys </p><p>2. U.S. Environmental Protection Agency: prospective site in USDW </p><p>hydrofrac investigation (no longer involved in fieldwork) </p><p>3. U.S. Geological Survey: Groundwater monitoring </p><p>4. U.S. Fish and Wildlife Service: Rare and endangered species </p><p>5. U.S.D.A. NRCS: soil surveys, erosion </p><p>6. U.S. Army Corps of Engineers: Stream water quality, sedimentation </p><p>7. PA DCNR (Geological Survey): Drill site monitoring and completion </p><p>8. Pennsylvania DEP: Fish and macroinvertebrate surveys </p><p>http://www.usgs.gov/http://www.portal.state.pa.us/portal/server.pt/community/dep_home/5968http://www.fws.gov/</p></li><li><p>19 </p><p>Second Test Site Study </p><p> Energy Corp. America (ECA) drill site in Greene Co., PA </p><p> Old, vertical Upper Devonian well present on site, </p><p>located between two, parallel Marcellus laterals. </p><p> Vertical well used for microseismic geophone string </p><p> ECA allowed a volatile tracer to be placed in frac fluid. </p><p> Upper Devonian well will be monitored and sampled to </p><p>determine if volatile tracer moved into shallower gas </p><p>sands from Marcellus after the frac. </p><p> Test hypothesis that the greatest risk of upward gas </p><p>migration occurs when an overpressured reservoir is </p><p>hydraulically fractured and just starting to be produced </p><p> Once pressure drops to hydrostatic or less, all flow is </p><p>into the wellbore. </p></li><li><p>20 </p><p>DOE Shale Gas Environmental Risk Assessment Goals </p><p>Assess short/long term and cumulative </p><p>environmental impacts. </p><p>Define engineering risks. </p><p>Data-based, scientific investigations of </p><p>impacts and processes. </p><p>Outcomes </p><p>Rigorous study with conclusions supported </p><p>by well-documented data </p><p>Benefits </p><p>Information-based regulations and </p><p>indicators for regulatory monitoring </p><p>Improved management practices for shale </p><p>gas production to mitigate problems </p><p>Create a more informed environmental </p><p>debate </p><p>Utica Shale, New York </p></li></ul>